3 Blocks I think. The Manaseer Monocle will tell you with more precision, though. Plus, you can combine the Manaseer Monocle with any (Botania) Bauble to give that Bauble the effect and looks.
Heh, you don't even need ComputerCraft ;o Just a simple repeater system would work.. although CC would make it a lot easier to make sure that you drop them in the right order. Plus, programming stuff like that is kinda fun. ;o
So basically it removes the fun mechanics from the game. Why would you even WANT to automate the Gaia Guardian, anyway? Two fights and you have enough Gaia Spirits to make everything you could ever need. And if you're just using it for the Daybloom use (even though Overgrowth Seeds make Dayblooms work as they used to anyway) ... well, I just hope you're not playing on a server.